Interesting as a historical artefact in its own right. Masquerading as a chronicle of real events, it's hilarious how inaccurate it clearly is, and I'm surprised it was taken as fact for so many centuries (dragons, Trojans and all). The only other way to view it is as fiction, on which count it doesn't hold up well at all, with poor pacing and a slightly rambling style. I'd recommend reading Books 5–6 and 8–11, which are the ones that set up the legend of King Arthur. The rest I'd skip.